CN112646186B

CN112646186B - Method for preparing organic silicon resin coating by utilizing hydrolytic polymerization of organic silane

Info

Publication number: CN112646186B
Application number: CN202011484187.9A
Authority: CN
Inventors: 陈晋阳; 马国丽; 杨云凡; 洪晓敏; 杨丁卿
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2020-12-16
Filing date: 2020-12-16
Publication date: 2021-10-12
Anticipated expiration: 2040-12-16
Also published as: CN112646186A

Abstract

The invention discloses a method for preparing organic silicon resin coating by utilizing hydrolytic polymerization of organosilane, wherein under the high-temperature hydrothermal condition of 150-200 ℃, organic siloxane is firstly hydrolyzed to generate silanol, and the silanol is polymerized at high temperature and high pressure to obtain polysiloxane. Because the mixed solvent of ethanol and water is generated in the hydrolysis and polymerization processes, the polysiloxane generated by the reaction can be dissolved in the mixed solvent to obtain the organic silicon resin coating. By the high-temperature high-pressure hydrolytic polymerization, the hydrolysis process which needs acid catalysis under the condition of heating reflux is avoided, and simultaneously, the ethanol and water generated in the synthesis process are used as a mixed solvent to obtain the organic silicon resin coating. The silicone resin coating prepared by the method has a long shelf life in the mixed solvent because of no residual acid.

Description

Method for preparing organic silicon resin coating by utilizing hydrolytic polymerization of organic silane

Technical Field

The invention relates to the technical field of synthesis of organic silicon resin, in particular to a method for preparing an organic silicon resin coating under a high-temperature hydrothermal condition.

Background

The organic silicon resin is a high molecular weight, three-dimensionally crosslinked polymer compound whose basic structure is a main chain composed of silicon atoms and oxygen atoms. The silicone resin has excellent weather resistance, heat resistance, water resistance, chemical stability, electrical insulation and the like. Silicone resins prepared using organosiloxanes having high hardness, high transparency and water resistance are known as glass resins, in which the [ CH ] is low₃]/[Si]The methyl silicone resin coating has high hardness and friction resistance, and is a high-quality wear-resistant protective coating for transparent optical devices.

At present, organic silicon resin is prepared by hydrolyzing and polymerizing organic siloxane monomers, which is mainly realized by hydrolysis, condensation and other reactions. For example, organic triethoxy siloxane and hydrochloric acid solution are reacted under reflux at a certain temperature, in the process, silanol is firstly obtained by hydrolysis through acid catalysis, meanwhile, byproduct alcohol is released, after a certain time of reaction, alkali such as hexamethyldisilazane is added to neutralize hydrochloric acid, and then the temperature is raised to evaporate ethanol and water. And then further condensing and dehydrating the silicon hydroxyl groups of the silanol or further condensing and dealcoholizing the silicon hydroxyl groups of the silanol and the silicon alkoxy groups of the reaction raw material siloxane to finally obtain an organic siloxane polymer with a proper amount of silicon hydroxyl groups, reducing the temperature to a proper value after reacting for a certain time in the process, and dissolving the obtained siloxane polymer in ethanol in a reaction system to obtain the ethanol solution coating of the organic silicon resin. The method needs acid as a catalyst, not only acid pollution exists in the process, but also improper control is performed in the acid catalysis process, so that silanol is easily polymerized in the hydrolysis stage, gel is generated, and the liquid phase coating with uniform dispersion is difficult to obtain.

Disclosure of Invention

The invention aims to solve the technical problems, and provides a method for preparing an organic silicon resin coating by utilizing hydrolysis polymerization of organosilane, which directly hydrolyzes organosiloxane without acid catalysis, and an alcohol-soluble siloxane polymer generated in the hydrolysis process obtains a uniformly dispersed liquid phase coating, so that the method is green and environment-friendly, and has a long quality guarantee period in a mixed solvent.

In order to achieve the purpose, the invention adopts the following technical scheme:

the method for preparing the organic silicon resin coating by utilizing the hydrolytic polymerization of the organic silane comprises the following steps:

s1, weighing organic siloxane and water in a certain proportion;

s2, adding siloxane and water into a hydrothermal high-pressure kettle, wherein the volume of the liquid is 70% of the volume of the high-pressure kettle, and sealing;

s3, heating the hydrothermal high-pressure kettle to 150-200 ℃, and enabling the materials to generate high pressure at high temperature, wherein the high pressure is usually 0.6-2.6MPa, and the hydrolysis polymerization reaction of siloxane is carried out under the high-temperature and high-pressure condition for 1-3h, wherein the reaction time and the temperature are key elements for controlling the molecular weight of the generated organic silicon resin, and the molecular weight of the organic silicon resin is too large and is likely to be insoluble in a mixed solvent to form gel precipitation, so that the coating cannot be obtained;

and S4, after the reaction is finished, opening the hydrothermal high-pressure kettle after the hydrothermal high-pressure kettle is cooled to room temperature, and pouring out a product, namely the organic silicon resin coating.

Preferably, the organic siloxane is methyl triethoxysilane or phenyl triethoxysilane.

Preferably, the weight ratio of the organic siloxane to the water in the step S1 is (3-5): 1.

the invention has the beneficial effects that:

the invention uses the weight ratio of the organic siloxane to the water (3-5): 1, adding the mixture into a hydrothermal high-pressure kettle, heating to 150-200 ℃ for reaction for 1-3h to obtain a homogeneous transparent organic silicon resin coating, directly hydrolyzing the organic siloxane by using the high activity of water under high temperature and high pressure without acid catalysis, polymerizing generated silanol after hydrolysis to obtain siloxane polymer, and dissolving the siloxane polymer in the alcohol generated in the hydrolysis process to obtain the uniformly dispersed liquid phase coating. The method is carried out at high temperature, so that the process is efficient, the reaction time is short, alcohol is obtained without steaming out, the process is simple, acid or alkali is not needed to be used as a catalyst in the process, the reaction is carried out in a closed system, no volatile component escapes, and the whole process is green and environment-friendly. In addition, the silicone resin coating prepared by the method has a long shelf life in the mixed solvent because of no residual acid.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.

Example one

The invention provides a method for preparing organic silicon resin coating by utilizing hydrolytic polymerization of organic silane, which comprises the following specific steps:

90g of methyltriethoxysilane and 30g of water are weighed out.

② charging the methyl triethoxysilane and water into a hydrothermal high-pressure kettle, making the liquid volume be 70% of the volume of the hydrothermal high-pressure kettle, sealing.

③ heating the hydrothermal autoclave, setting the stirring speed at 100r/min to 150 ℃, and keeping the temperature for reaction for 3 hours, wherein the pressure is about 0.6 MPa.

And fourthly, after the reaction is finished, turning off the heating, keeping stirring, stopping stirring after the hydrothermal reaction kettle is cooled to room temperature, opening the hydrothermal reaction kettle, pouring out the product, and obtaining homogeneous liquid, namely the methyl organic silicon resin coating.

Example two

The method for preparing the organic silicon resin coating by utilizing the hydrolytic polymerization of the organic silane comprises the following specific steps:

120g of methyltriethoxysilane and 30g of water are weighed out.

③ heating the hydrothermal autoclave, setting the stirring speed at 100r/min till the temperature reaches 180 ℃, and keeping the temperature for reaction for 1.5 hours, wherein the pressure is about 1.8 MPa.

EXAMPLE III

150g of methyltriethoxysilane and 30g of water are weighed out.

③ heating the hydrothermal autoclave, setting the stirring speed at 100r/min until the temperature reaches 200 ℃, and keeping the temperature for reaction for 1 hour, wherein the pressure is about 2.6 MPa.

Example four

The amount of the components and the polymerization parameters were the same as in the first example, except that phenyl triethoxysilane was used in this example.

EXAMPLE five

The amount of the components and the polymerization parameters were the same as those in example two, except that phenyl triethoxysilane was used in this example.

EXAMPLE six

The amounts of the components and the polymerization parameters in this example were the same as those in example III, except that phenyltriethoxysilane was used in this example.

The invention provides an organic silicon resin coating which is prepared by utilizing the hydrolytic polymerization reaction of organic siloxane under the conditions of high temperature and high pressure. The organic silicon resin coating is directly smeared on a clean stainless steel sheet and cured for 24 hours at room temperature, the obtained coating has good transparency and the hardness is about 5H, and no appearance is generated after the coating is soaked in water for one week.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.

Claims

1. The method for preparing the organic silicon resin coating by utilizing the hydrolytic polymerization of the organic silane is characterized by comprising the following steps:

s1, weighing organic siloxane and water in a certain proportion; the weight ratio of the organic siloxane to the water is (3-5): 1; the organic siloxane is methyl triethoxysilane or phenyl triethoxysilane;

s2, adding organic siloxane and water into a hydrothermal high-pressure kettle, wherein the volume of the liquid is 70% of the volume of the high-pressure kettle, and sealing;

s3, heating the hydrothermal high-pressure kettle to 150-200 ℃, keeping the internal pressure at 0.6-2.6MPa, and carrying out a hydrolysis polymerization reaction on the organosiloxane for 1-3 h;